MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 87 
Hyalinia radiatula (Alder). 
1805 Helix nitidula var. 8 Drap., Hist. Moll. France, p. 117, pl. viii., ff. 21, 22. 
1821 — _ striatula Gray, Medical Repos., xv., p. 239 (without characters). 
1830 — radiatula Alder, Trns. Nat. Hist. Soe. North. Durh., ete., i., p. 38, no. 30. 
1830 — viridula Menke, Syn. ed. ii., p. 127. 
1841 — electrina Gould, Invert. Mass., p. 183, f. 111. 
1841 — janus Adams Mss. (olim) Shells Verm., Amer. Journ. Sei., xl., p. 273. 
1848 — pura var. 8 Pfeiffer, Monog. Helic., i., p. 96. 
1853 — _ petronella Charp. in Pfeiffer, Mon. Hel. Viv., iii., p. 95. 
1840 Zonites radiatulus Gray, Turton’s Man., p. 173, pl. xil., f. 137. 
1855 — (Aplostoma) striatula Moq.-Tand., Hist. Moll., ii., p. 86, pl. ix., ff. 19-21. 
1864 — dwumontianus Bourguignat, Mal. Aix les Bains, p. 26. 
1858 Helicella radiatula Bellars, Ill. Cat. Br. L. & F.W. Shells, p. 16, pl. 2, f. 39. 
1876 Hyalina striatula Weinl., Weiechth. Schwab. Alb., p. 38. 
1884 — pellucida Lehnert, Science Record, June 16, 1884, p. 172. 
1891 Vitrea (Polita) radiatula Smith, Journ. of Coneh., vi., p. 339. 
1897 Hyalinia hammonis Westerlund, Syn. Moll. Extram., p. 34. 
ISTORY.—Hyalinia radiatula (radiatula, 
tinely or delicately radiate) though first 
noticed and named by Dr. Gray in 1821, 
was not described or figured by lim, so 
that Alder’s name published in 1830, which 
was accompanied by a full description, 
takes precedence. 
Strém, the Norwegian, in 1765, described 
and figured in the ‘ Trond. Selsk. Skrift.,” 
iii., p. 435, pl. 6, f. 16, a Hyalinia under 
the name of hammonis, which is regarded 
by many as the same as our species; but 
this opimion is by no means universally 
held, as Dr. L. Pfeiffer in his great work 
‘““Monog. Helic. Vivent.” regarded Strém’s 
species as synonymous with Hyalinia nitida, 
and subsequently as identical with //. pura, 
while Binney and Bland considered it more 
properly referable to H/. fudva, and ‘Tryon 
and later Dr. Dall consider its identitica- 
tion with 7. radiatula as very doubtful. 
After a careful examination and study of 
Strém’s original description and figure (see 
p- 88) I have decided to retain the well-known name radiatula, a name 
upon the precise identification of which there can be no dispute. 
Considerable difference of opinion also exists as to the precise relation- 
ship between /7. radiatulu Alder, H. viridula Menke, H. petronella Charp., 
and H. electrinw Gould, whether they should be regarded as really 
synonymous or as closely allied species, but as no structural differences 
have hitherto been demonstrated, the interests of the study will be best 
served by regarding them as geographical races of the typical rudiatula. 
he present species is here dedicated to the well-known conchologist, 
Herr Stephan Clessin, of Ochsenfurt, Bavaria, for some time editor of 
“ Malakozoologischer Blitter,” and author of numerous valued publications, 
who has paid some attention to the lingual dentition of the present species, 
